This invention relates generally to a cooling system and, more particularly, to a flywheel energy storage system for maintaining fan speed of a cooling fan on an internal combustion engine.
Internal combustion engines include many components that generate heat during operation of the internal combustion engine. These components may include, for example, pistons, rings, injectors, valves and the like. Above a certain temperature, the components are likely to overheat potentially resulting in a failure of the internal combustion engine. Accordingly, these components must be cooled during the operation of the internal combustion engine in order for the internal combustion engine to function in the most efficient and economical manner.
To cool these components, a cooling system is used during the operation of the internal combustion engine. One type of cooling system is a fan driven system which is driven via a pulley and belt system by the internal combustion engine. By using a belt driven fan system, the rotation of the fan will generate an air flow which will cool the components, i.e., decrease the operating temperature of the components of the internal combustion engine.
The rotation of the fan of these type of systems is dependent on the speed (revolution per minutes) of the internal combustion engine. That is, a higher engine speed will result in a higher fan speed. Of course, the higher fan speed will generate a higher air flow over the components of the internal combustion engine. This higher air flow, in turn, will cool the components of the internal combustion engine thereby ensuring the reliability and efficiency of the engine. Thus, in a high speed mode of the internal combustion engine, typical fan driven systems adequately cool the engine by generating a sufficient air flow to cool the engine components.
It follows then that at lower engine speeds, and in particular at an idle speed of the engine, the fan speed will not generate a high air flow. In these states, the engine components will not be adequately cooled, even though the components may still exceed a threshold temperature. This can result in a catastrophic failure of the engine components and thus significantly reduce the life of the internal combustion engine.
It is of critical importance to cool the engine components at all times during the operation of the internal combustion engine, regardless of the operating speed of the internal combustion engine. First, the engine components still generate a significant amount of heat during the idle or low speed of the internal combustion engine. Second, the components may be at a very high temperature during the low or idle speed due to the fact that the internal combustion engine was previously at a higher engine speed, e.g., generating a higher temperature. Third, it is an excellent opportunity to cool the engine components at a low or idle speed prior to the engine performing at a higher speed and thus generating higher component temperatures.
U.S. Pat. No. 3,882,950 to Strohlein, which was issued on May 13, 1975, shows an engine with a cooling system. The engine cooling system includes an engine having a fan coupled directly thereto. As the engine speed increases so will the fan speed. Conversely, however, when the engine speed decreases so will the fan speed. Thus at low or idle engine speeds, the fan may not be capable of generating a sufficient amount of air flow to cool the components of the engine. This may lead to a failure or, in the least, an overheating of the engine.
The present invention is directed to overcoming one or more of the problems as set forth above.
In one aspect of the present invention a fan is coupled to both a flywheel and a clutch assembly. The flywheel stores energy.
In another aspect of the present invention a method of cooling an internal combustion engine using a fan is provided. In the method, a flywheel stores energy and a clutch drives the fan when the speed of the internal combustion engine is at or above a predetermined speed. The fan rotates independent of the internal combustion engine while maintaining a speed of the fan via energy stored in the flywheel.
In still another aspect of the present invention, an internal combustion engine is provided with an flywheel energy storage system. The internal combustion engine includes components which are cooled by a fan. A flywheel and clutch bearing assembly are coupled to the fan.